title: Dopaminergic medication counteracts conflict adaptation in patients with Parkinson's disease.
abstract: OBJECTIVE
  We tested the role of dopamine in conflict-induced behavioral adjustments by evaluating the effect of dopaminergic medication on conflict adaptation in Parkinson's disease (PD) patients.
  
  
  METHODS
  Nine PD patients performed a vocal Stroop task on two separate testing occasions: once on their regular medication and once after overnight withdrawal.
  
  
  RESULTS
  In line with previous studies (e.g., Bonnin, Houeto, Gil, & Bouquet, 2010), patients displayed no conflict adaptation when tested on medication. However, the same patients tested off of their medication did display a conflict adaptation effect in that the size of the interference effect was reduced after incongruent trials compared with after congruent trials.
  
  
  CONCLUSIONS
  This difference is discussed in terms of an inverted U-shaped relation between dopamine and performance, according to which dopaminergic medication has detrimental effects on PD patients' performance by overdosing brain regions that are relatively spared in the initial stage of the disease, including the ventral striatum and prefrontal cortex.
authors.affiliation: Department of Experimental Psychology, Ghent University.
authors.forename: Wout
authors.initials: W
authors.lastname: Duthoo
authors.forename: Senne
authors.initials: S
authors.lastname: Braem
authors.forename: Femke
authors.initials: F
authors.lastname: Houtman
authors.forename: Nathalie
authors.initials: N
authors.lastname: Schouppe
authors.forename: Patrick
authors.initials: P
authors.lastname: Santens
authors.forename: Wim
authors.initials: W
authors.lastname: Notebaert
mesh_terms: D000223:Adaptation, Psychological; D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000009:adverse effects / Q000627:therapeutic use*; D003220:Conflict, Psychological; D015259:Dopamine Agents / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007980:Levodopa / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy* / Q000503:physiopathology / Q000523:psychology*; D011930:Reaction Time; D057190:Stroop Test
chemical_list: D000978:Antiparkinson Agents; D015259:Dopamine Agents; D007980:Levodopa